Start from the opening, not from the drawer
Cabinet work goes wrong when people design the drawer they want and then try to make the cabinet accept it. Everything downstream is determined by the opening, and every dimension on this page is derived from it by subtraction. Opening width less the slide clearance gives the box width. Opening height less the reveals, divided by the drawer count, gives the front height. Box height is the front height less however much you want the box to sit below the top of its front. Cabinet depth less an inch, rounded down to a standard slide length, gives the box depth.
None of that is difficult. What makes it error-prone is that the subtractions are small, several of them are doubled, and a single missed sixteenth is the difference between a drawer that glides and one that binds against a slide that will not compress.
The clearance is a specification, not a preference
Standard side-mount ball bearing slides need one half inch on each side, one inch total. That is not a comfort margin you can shave; it is the thickness of the slide mechanism itself, and a box a sixteenth over will not physically enter the opening. Epoxy-coated side mounts use the same half inch. Undermount slides are a different family altogether and their deductions vary noticeably by manufacturer, because the box has to sit on top of the mechanism and engage locking devices at the back.
This page ships a default per slide type and then lets you override it, and the override is the field that matters. The instruction sheet in the box you bought is the authority on that number. Read it before cutting the box parts, not after.
Inset and overlay change only the fronts
Switch between inset and overlay and the box dimensions barely move; what changes is the fronts. Inset fronts live inside the opening with a reveal all round, so the height available is the opening less one reveal more than there are drawers: three drawers means four reveals. Overlay fronts sit on the face frame and cover it, so they are larger than the opening in both directions and the reveals only appear between adjacent fronts.
Inset is far less forgiving. An eighth inch reveal that varies by a thirty-second along its length reads as crooked from across the room, and it is a direct function of how square the opening was built. Overlay hides a surprising amount of that. If the carcase is not dead square, this is worth knowing before you commit to a style.
The cut list and what it assumes
The list here describes the most common shop-built box: four sides of the same thickness, the front and back captured between the two sides, and a bottom panel sitting in a groove ploughed around the inside. That construction means the front and back are the box width less twice the side thickness, and the bottom picks up the groove depth on all four edges, so it is wider and deeper than the clear inside dimension.
If you build differently the arithmetic changes and you should adjust it rather than trusting this list. Rabbeted corners, dovetails with the pins in the sides, and boxes with a captured bottom rather than a grooved one all shift the numbers. Feed the resulting parts into the cut list optimizer to work out how they land on your stock, or the plywood sheet calculator if the boxes are coming out of sheet goods. Where a shelf rather than a drawer goes into the same opening, the shelf sag calculator is the one that decides whether the span works.
Questions people ask
How much narrower than the opening should a drawer box be?
One inch total for standard side-mount ball bearing slides, half an inch on each side. That is the mechanism thickness, not a tolerance, so it is not negotiable and a box built a sixteenth wide will not fit at all. Undermount slides are different and vary between manufacturers, typically taking a little less in width but adding requirements at the back and underneath. Whatever type you have, the instruction sheet gives the exact deduction for that model, and it is the number to build to. Measure the opening at the front, the middle and the back before you cut, because a carcase that has bowed will bind even with the clearance correct.
How tall should the drawer box be relative to its front?
Shorter, and usually by about an inch, though the reason varies. The box needs to clear the drawer above it as it comes out, the slide has to mount somewhere on the box side, and the front has to cover the box edge so no plywood shows. The default here is an inch below the front, which suits most side-mount work. With undermounts the relationship is set by the slide because the box rides on top of it, and the required drop and the box bottom setback both come from the instruction sheet. When in doubt, build one box and test it in the opening before making the rest.
What slide length should I use for my cabinet depth?
The longest standard length that leaves about an inch of clearance behind it inside the cabinet. Slides come in two inch steps, so a 23 inch inside depth takes a 22 inch slide and a 21 inch depth takes a 20 inch. Going longer than the cabinet allows means the drawer will not close; going shorter than necessary throws away drawer capacity for nothing. This page picks the length for you and reports it, but check it against what your supplier actually stocks, because some ranges skip sizes.
Why do my inset drawer fronts look uneven when the measurements were right?
Almost always because the opening is not square or not parallel, and inset work has no way to hide that. A reveal of an eighth inch that opens to three sixteenths at one end reads immediately as wrong, even though the front itself is a perfect rectangle. Check the opening diagonals before you size anything. If they differ, you can either fix the carcase, fit each front individually to its own gap rather than cutting them all to one size, or switch to overlay fronts, which sit on the frame and cover a great deal of variation.
Should I make all the drawers in a stack the same height?
It is the default this page assumes because it makes the arithmetic clean, but it is not the usual choice in furniture. A stack with a shallow drawer at the top and progressively deeper ones below is both more useful and more conventional to look at. If you want graduated drawers, work out the total front height available here first, then divide it deliberately rather than evenly, keeping the reveals the same throughout. The box dimensions for each drawer then follow from its own front height using the same drop.